Machine-switching telephone-exchange system



W. MATTHIES MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM Jan. 8', 1924. 1,480,215

FiledJFeb. 24. 1919 8 Sheets-Sheet 1 Jan. 8 1924. 1,480,215

- w. H. MATTHIES MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM Filed Feb. '24, 1919 a Sheets-Sheet 2 i I: L7 293 596 297 hie/#01 W/7/l'am h. Maff/r/bs I Jan. 8 1924. 1,480,215

w. H. MATTHIES MACHINE swncnme TELEPHONE EXCHANGE SYSTEM Filed Feb. 24, 1919 s Shets-Sheet s Jab. s, 1924. 1,480,215

W. H. MATTHIES MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM Fi led Feb. 24 1919 8 j fig. 4. 3

Jan. 8 1924.

W. H. MATTHIES v MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM Filed Feb. 24

Jan. 8, 1924. 1,480,215

W. H. MATTHIES MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM Filed Fi). 24 1919- 8 Sheets-Sheet 6 4 Fly. 6.

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W. H. MATTHIES MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM i a .720 2 E /n van/0r:

Jan. 8,1924. 1,480,215.

W. H. MATTHIE S MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM File d Feb. 24, 1919 8 Sheets-Sheet a Fatented Jan. S, 1924.

UhllgE WILLIAIVI NIATTEIES, OF HAGKENSACK, NEV] JERSEY, ASSIGNOR. TO WESTERN ELECTRIC COMPANY, INCORPORATED, OE NEW YORK. N. Y., A CORPORATION OF NEW YORK.

I'VEACHINE SW-ETGHIHG TELEPHONE-EXCHANGE SYSTEM.

Application fi led February 24, 1919. Serial No. 273,700.

matic switch either to a called line or toanopera-torts position, in. wlliich a, calling subscriber is enabled to release a; automatic switch when aconnectionv isentended' to a called, line, and to operate a su )errisory signal be said sithe oper ch when a connection is extended to a-tors position.

provis nof an arrangement wherein the calling sub her is enabled; to release the mitoniatic s .ch when. a connection, is extended either to a called line or to the op erzrtors position and means. rendered cf.- fective by the v response of the operator whereby the calling subscriber: may control the ()PQZTRUOH of a supervisory signal. at the operators position. without releasing the automatic switch.

A: liurther teature relates to system. of.

thc abore character in which an auxiliary switch for controlling. the operation of, the automatic switch is arranged to assume one position when. a connection. is extended to the 0 connection is extended. toa called line wherein the calling subscriber is enabled; to rclease the automatic switch, provided the auxiliary switch is in. one oi its positions.

and to control a supervisory signal at, the operator-7s position without releasing the automatic switch it said auxiliary switch is standing in the other of its positions.

Figure 1 shows a, subscribcrs line and a:

first line finder I Figure 2 shows. a cord circuit comprising a second line finder and a first; group solect r;-

l. urcs 3 and lshow a register set and 110 following is a full, clear, 4

elephone exchan e systems, and, more;

lore the operator without; releasing nure oil the invention relates to the aerator. and another position when a common arrangement for the timely delay of a lllOlllliOllllg. signal;

Figure 5 shows a second group selectorfor local connections l igure 6 shows a final selector;

Figure 7, shows a second group selector on the incoming end oi a two-wire trunk line;

Figure 8 shows a trunk line extending to a recording or a toll operators:position;

Figure 9 shows a trunk line extending to. the information desln, complaint desk, wire chi'efs desk, etc. and;

Figure-1O shows a. trunk line extending to. a distant manual: exchange.

The system disclosed as embodied in the p :esent invention will be best understood from a, desc ion of the operation thereof.-

The operation of the circuit of the first line finder, the cord and the final selector is briefly such that when a line relaiy 201- is energized the common starting relays 2051s providea circuitforthe energization of the. power magnets 211 of the free first line finders. in, the group. The brush carriages of the tree first line finders rotate, and; 111;

reaching terminal 210' or; the calling line test relay 2145 of a line finder is energized and the teiminali 21.0 is made busy through the connection. of the-low. resistance-windingof relay 21 and: the windingol relay 212 in parallel to the high resistance winding of relay 21d. Relay 212 disconnectsthe power ma et 2111 and provides. a circuit for the oneization of t e holding ma net 215; and:

t: L: 2: r

l-he brush.

connnon starting relays 216. carriage of in. first line find: is. arrested, and a circuit is provided: for the free sec 0nd. line finders which have accessto this first line finder. are divided. in pairs and when the cordsa're free, the corresponding sequence switches 220 are held; eitherin. position. 18 or position 1. v

which the sequence switch 220. is in position 1 is able to search for a calling first line finder; Relay 222-. of: the cord is then energized. in a c' 'cuitl over the front contacts of the common. starting relays 216; The power magnet 22.1 is thenienergized ina circuit over the front contact of relay 222 and On reaching terminal 230 the. test relay 23 1 The second: line: finders Only. the line finder of a cord. on.

is energized, relay 232 is brought into the same circuit, terminal 230 is made busy, and relay 232 when energized causes the energization of sequence switch 220 in a circuit over front contacts of relays 2 2 and 222. Soquence switch 220 starts fl'Osl'l position 1 and moves into position a. V1 hen sequence switch 220 passes position 2, the high resistance winding of relay 2341- is disconnected at sequence switch contact 227 bottom, and the energization o relay 23-1 is maintained over its low res ance winding. in position 3 oi? sequence switch a circuit is established for the energization of relay 235 of the cord, relay 233 of the lirst line tin der and cutoff relay 207 oil the calling line, whereby relay 201i is deenergized and the brush carriages oi the remaining free first and second line ill'lClQ"S are arrcred. The release relay 231 together with retardation coil 23? is brought into connection with the calling line.

In position 4; of sequence switch 220 the searching sequence switch 280 of the cord is energized and a free register set searched for. Assuming the register set in Figs. 3 and l tree, a connection with this register is obtained as soon as sequence switch 280 reaches position 1 or 7. Relays 23a and 232 are thereby energized in a circuit over con ductor 293, contact 322 top of sequence switch 320 and left-hand winding of relay 323. Sequence switch 280 is arrested whereas sequence switch 220 is advanced into position The calling subscribers line is broughtinto connection with the secondary winding 01 dialing tone coil 32 i and the stepping relay 325 of the register set. Relay 323 when energized provides over its front contact and right-hand winding a circuit or the energization of sequence switch 320, which controls the connection oi: the registers in succession in a circuit which is under the control of the stepping in relay 325. Sequence switch 320 starts from position 1 and moves into position 3. In positions 2 and 3 01 this sequence switch the primary winding of the dialing tone coil 324 is connected over sequence switch contact 332 in a circuit with an interrupter 333, and the calling subscriber when receiving the sharp dialing tone winds up the dial to send the first figure of t ne wanted numher. Then sequence switch 320 reaches position 3, relay 323 is deenergized and relay 326 energized in a circuit over back contact of relay 323 and sequence switch contact 327 bottom. lhe ten thousands register 100 is energized in a circuit over sequence switch contact 328 top, back contact and right-hand winding of relay 329, sequence switch contact 330 top and front contacts of relays 326 and 325. Relay 329 remains thereby deenergized since its lefthand differentially wound winding is connected in a parallel circuit over retardation coil 331. Register 100 starts from position 0, and in closing its local contact l0l provides a shunt around the right-hand winding of relay 329, which is then energized, and in opening its back contact disconnects the register. Relay 329 remains energized untilthe line circuit is opened at the dial and relay 325 is deenergized. Relay 329 in closing its back contact again prepares the circuit for register 100 which receives current as soon as relay 325 is again energized. @ver the back contact of relay 329 is also connected in parallel to the register the relay 337, which when energized, maintains over its front contact the closure otthe circuit for relay 329. Relay 33? remains energized until the register reaches its next position and its local contact is opened. On the lastinterruption at the dial, relay 325 remains deenergized for a comparatively long time and the slow operating relay 334 is energized in a circuit over seswitch contact 3&2 bottom, and

guence back contact 0t relay 325. Relay 323 is then energized in a circuit over trout contact of relay 334. Sequence switch 320 is again energized, starts from position 3 and moves into position 5. Relay 325 is thereby again energized over the calling line before sequence switch 320 reaches position l When the sequence switch passes into position l, an additional energization or register 100 is provided in a circuit over sequence switch contact 330 bottom, the ten thousands register is then disconnected and the circuit is prepared for the thousand registers 110 over sequence switch contact 328 bottom. Relay 326 is deenergized during the time sequence switch 320 moves between positions 3 to 5. and the first energization of register 110 takes place immediately the front contact of relay 326 is closed. Register 110 starts from position 0, and in closing contact 111 the right-hand winding oi? relay 329 is short-circuited and relay 329 opens its back contact, and the registercompletes its step under the control of its contact 111 and is arrested in position 1. Relay 337 is now connected in parallel to register 110 and maintains the energization of relay 329 during the time contact 111 is closed. When the dial is released a second time, register 110 is brought to a position corresponding to the figure dialed, and sequence switch 320 is advanced from position 5 into position 8, in which the hundreds register 120 is connected in the stepping circuit over sequence switch contact 335 top, and is set up according to the third set of impulses from the dial. Sequence switch 320 is then advanced from position 3 into position 10, in which the tens register 130 is connected in the stepping circuit over sequence switc switch 320 is advanced-from position 10 into position 12 in which the units register 140 is connected in the stepping circuit overv sequence switch contact 336. When the dialing is completed, sequence switch 320 is advanced from position 12 into position 14.

The capacity of the exchange is assumedto be twenty thousandlines. First and second group selectors and final selectors are therefore provided. The register registers the odd and even ten thousands, whereas the thousands register 110 controls the selection of the correspondinglevel at the first group selector. The position of the registers determines the translation from the decimal number system of the wanted subscriber line to the system of the s' 'itches, and register 100 determines the translation for the first group selector. The.

setting up of the first group selector takes place during the time the subscriber con tinues the dialing, and the operation of the trip spindle of the first group selector is delayed until the first two impulse series are completed on the dial. Thiscorresponds to sequence switch 32.0 leaving position 5. In position 6 of sequence switch 320 a circuit is closed for the energization of sequence switch 350 over contact 352 top, back contact of relay 353, contact 103 of register 1.00 and contact 338 top of sequence switch 320. Sequence switch 350, which controls the connection of the registers in succession for the control of the fundamental circuit of the selectors, starts from position 1, and under the control of its local contact 3.5.1, moves into position 3. In position 2 of sequence switch 350 the right-hand winding of relay V 359 is energized in a circuit over back contact of stepping out relay 3.55 and sequence switch contact 354. Relay 359 keeps open at its back contact the circuit for resetting the registers.

Assuming that the. number of the wanted line is 124-53. lVhen the dial is wound up to digit 1 and then released, the register 100 makes nine steps under the control of the dial and one step under the control of contact 330 bottom. The register 100 is therefore again in its position 0. On the second digit, register 110 has been energized eight times under the control of the dial and is therefore in position 8. When sequence "switch 350 reaches position 3 the funda mental circuit is closed over contact 356 top of sequence switch 350, back contact of re- 357, windin of stepping-out relay 3555, contact 358 bottom of sequence switch 350, common wire 296 and winding of'relay' 222. Both relays 222 and 355 are'energized. Sequence switch 220 starts from position 5 and moves into position 6, in which the. trip sp ndle magnet 248 is'energized. The trip spindle rotates and'proiluccs, at its contact 250 top, shortecircuitings around the wind.- ing of relay 3.55. As soon as the back contact of relay 355 is closed, theregister 110 is energized in a circuit overleft-hand back contact of relay 3.60, contact 1130f register 110, contact 361 top of sequence switch 350, back contact and left-hand winding of relay.359, back contact of relay 355 and se-' quence switch contact 354. Simultaneously with the energization of register 110, relay 362 is also energized and provides over its front contacta bridge to the contact of relay 355. Relay 362 in the circuit for the outgoing impulses serves the same purpose as relay 337 in the circuit of the incoming impulses, and enables a safe operation of the register. Register 110 starts from position 8 and moves into position 9. In the meantime, trip spindle contact 250 has been opened, the stepping relay 355 leaves its back contact, and relay 359 is deenergized. On the following closure of. contact 250, relay 355 is again deenergized, and register 110 is energized, and moves out of position 9 into position 0. On the following deenergization of relay 355, the right-hand winding of relay 357 is energized in a circuit over sequence. switch contact 363 top, contact104 of register 100, contact 114 of register 110,

contact 364 bottom and contact 361 top of When contact 351 is closed and the lefthandwinding of relay 359 is short-circuited, this relay is energized and maintains its en- 'ergization over back contact of relay 355.

After contact 250 of the trip spindle is opened, relay 222. is deenergized. Sequence switch 220 starts from position'6 and moves into position 7, in which the test. relay 23.4

is connectedwith the test brush 252 of the first group selector. Relay 222 is now energized in a circuit over conductor 293, back contact of relay 339 and contacts 340 top of sequence switch 320. The power magnet 241 of the group selector brush carriage is energized in a circuit over front contact of relay 222. The brush carriage rotates in the well-known manner, the brushes moving along the terminal row determined by the position ofthe trip spindle. Inreaching the test terminal leading to a free second group selector, relay 234 is energized in a circuit over test brush 252, contact 401 of sequence switch 420 individual to the second group selector, and resistance 402. In parallel to resistance 402 a hi h resistance release rela 7 b V y 403 is also connected. .Relay 234 brings its low-resistance wind ng and the winding of relay 232 in parallel to its high resistance all winding, and makes the terminal of the group selector busy. Relay 232 is energized, the power magnet 241 is disconnected, se quence switch 220 and the holding magnet 245 of the first group selector are energized, the brush carriage is arrested, and sequence switch 220 starts from position 7 and moves over position 8 into position 9, in which the fundamental circuit is prepared on sequence switch cont-acts 247 top and 255 bottom to the scond group selector pending the closure of the fundamental circuit at the register set.

Sequence switch 350 remains in position 4 until the third series of impulses at the dial has been completed and sequence switch 320 has left position 8. A circuit is then established for the energization of sequence switch 350 over contact 363 bottom and contact 338 bottom of sequence switch 320. Sequence switch 350 starts from position 4 and moves into position 6. The fundamental circuit containing rela 22 of the second group selector is now closed over contact 404 of sequence switch 420, contact 247 of sequence switch 220, contact 286 of sequence switch 280, conductor 2%, contact 358 bottom of sequence switch 350, relay 355, back contact of relay 35?, contact bottom of sequence switch 350, right-hand back contact of relay 365, conductor 297, contact 23? of sequence switch 380, contact 255 ct sequence switch 220 and contact 405 ct sequence switch 420. Both relays and are energized. Belay 359 is deenergized. Sequence switch 420 is energized in a circuit over its contact 406 and front contact of relay 422. Sequence switch 420 starts from position 1 and moves into position 2, in which the trip spindle magnet 408 is energized in a circuit over sequence switch contact 407 and front contact of relay 422. The trip spindle rotates and provides at contact 410 top, over sequence switch contact 409, short--c.ircnitings in the fundamental circuit. lhe resistance 402 is disconnected at contact 401 from terminal in position 2 cl? sequence switch 420, and the high-resistance relay 403 is left alone in the circuit which incluces the test terminal. Relay 234 is deenergized and opens its left-hand winding, while relay 403 remains energized over the right-hand winding of relay 234.

ffhen relay 365 is deenergized, register 120 is energized in a circuit over contact 122, contact 36% bottom of sequence switch 350 and back contact of relay 359. Register 120 starts from position 6 and moves into position 7, and when register 120 reaches position 0 under the control of relay 355, the register is disconnected, and on the following deenergization of relay 355, a circuit is established over contact 124 of register 120, contacts 361 bottom and 364 bottom olsequencc switch 350, contact 114 of regis ter 1.10, contact 104 of register 100 and sequence switch contact 303 top for the energization of relay 357 and sequence switch 350. The fundamental circuit is opened at the back contact of relay 357, and sequence switch starts from position 6 and moves into-its position 9. As soon as contact 410 of the trip spindle is also opened, relay 422 is deenergized and sequence switch 420 is energized in a circuit over its contact 411 top and back contact of relay 422. Se-

quence switch 420 starts from position 2 and opens the fundamental circuit on the group selector at contacts 404 and 405, con tact 404 being opened before contact 358 top of sequence switch 350 is closed. Sequence switch 420 moves into position 5, in which the left-hand high-resistance winding of relay 434 is connected over sequence switch contact 413 bottom with the test brush 412. The power magnet 431 of the brush carriage is thereby energized in a circuit over sequence switch contact 414 bottom and back contact of test relay 432. The brush carriage rotates, moving the brushes along the terminal row determined by the position of the trip spindle. ln reaching the terminals of a tree final selector, relay 434 is energized in a circuit over brush 412, contact 441 of sequence switch 450 individual to the final selector, and through resistance 442. i-i high resistance relay 443 is also connected in the circuit. Relay 434 brings its right-hand lowresistance winding over its front contact and winding of relay 432 in connection with brush 412, and makes the test terminal to this final selector busy, relay 432 is energized, disconnects at its back contact power magnet 431 and provides a circuit for the energization or sequence switch 420 over contact 406 top and frontcontact of relay 432. In parallel to the sequence switch over contact 411 bottom is connected the holding magnet 435 of the selector, the brush carriage is arrested and sequence switch 420 starts from position 5 and moves into position 10, in which the fundamental circuit is extended over sequence switch contacts 415 and 416 to the final selector. Terminal 412 is now connected over sequence switch contact 413 top, direct with the winding of relay 432, so that the right-hand winding of relay 434 is short-c-ircuited and this relay is deenergized.

Sequence switch 350 remains in position 9 until the tens and units registers have been set up under the control of the dial, and sequence switch 320 has moved into po sition 14, in which sequence switch 350 is energized in. a circuit over contact 352 top, right-hand back contact of relay 353 and contact 341 bottom of sequence switch 320. Sequence switch 350 starts from position 9 and'mo'i'es into position 10 in which the fundamental circuit is closed at the register set over right-hand back contact of relay 378 and sequence switch 'contact'379 top. Relay 452 at the iinalsele'ctor and relay 355 at-t-he register set are energized. Relay 359 is deencrgiaed. A circuit is closed for the energization of sequence switch450 over front contact of relay 4 2 and-contact 490 bottom. Sequence switch 450 starts from position 1 and moves into position 2, in which the trip spindle magnet 448 is energized in a circuit over front contact of relay The trip spindle rotates and provides at its contact 455 top short-circuitings of the fundamental circuit.

When relay-355 is deenergized, register 130 is energized in a circuitover contact contact 367 top of sequencev switch 350 and back contact of relay 359. Register 130 starts from position and moves into position After register 130 is restored to position i), under the control of relay 355, a circuit is established onfthe following deenergization of relay 355 over contact 134 of register 130 and contact 352 of'sequence switch 350 for the energization of the sequence switclrand' relay 357. The fundamental circuit is thereby opened, and sequence. switch 350 starts from position 10 and mores into position 12. After contact 351 is openech relay 357 is deenergized, and the fundamental circuit is again closed at its back contact. lV hen contact 455 of the trip spindle is also opened relay 452 is deenergized, and sequence switch 450 is energized in a circuit over back contact of relay 452 and contact 491 top. Sequence witch 450 starts from position 2 and moves into position The duration of the opening of the fundamental circuit at back contact of relay 357 is so selected that contact 447 of sequence switch 450 is opened before relay can be energized a second time over the fundamental circuit, whereas'the energizati on of this relay takes place before sequence switch 450 reaches position 5. The power magnet 461 of the brush carriage is now energized in a circuit over contact 492 top and the front contact of relay 452. The brush carriage rotates. moving the brushes along the sixth terminal row and a series of short-circuitiugs of the stepping relay in the fundamental circuit is again produced at comic! 457 top of the brush carriag'e.

.Vheu the relay 355 is deenergiz'ed, a circuit is established for the energization of. register 140 over contacts of relays 355 and 359, coi'itact 3,57 bottom of sequence switch and contact 142 of units register 140. After register 140 reaches positionO, under the control of relay 355, a circuit is established for the energizat-ion of 7 sequence swi'tcl'i and relay 357 at the following deenergization of relay 355 over contact 143 of register 140 back contact of relay 374, contact 144 of register 140 and contact, 352 bottom of sequence switch 350. The fundamental circuitis again opened and sequence switch 350 starts from position '12, and moves over positions 15, 16 and 17 (as will be hereinafter described) into position 1. in position 13 of sequence switch-350, a. circuit is established for the energization of relay 339 over contact 368 bottom of sequence switch 350, left-hand back contact of relay 365 and sequence switch contact 369. The cner 'ization of relay 339 causes the deenergization of relay 222 in the cord, whereby sequence switch 220starts from position 9. in position 10 of the sequence switch 220 the fundamental circuit of the register set is disconnected. Y Supervisory relay'262 and retardation coil 257 are connected to the final selector. lVhen sequence switch 220 leaves position 9 the subscribers line is again connected with relay 231 and retardation coil 237. in position 10 sequence switch 220 is energized in a circuit over back contact of relay 262. Sequence switch 220 moves over position 10 into position 11.

As soon as relay 325 atthe register set is deenerqized sequence switch 326 is energized in a circuit over contact 348 bottom and back contact of. relay 325. Sequence switch 320 starts from position 14 and moves into position 15. W hen sequence switch 350 reaches position 1, a circuit is established for the energization of relay 323 over contact 322 bottom of sequenceswitch 320 and contact bottom of sequence. switch Sequence switch 320 is again energized over front contact of relay 323, starts from posit-ion 15 and moves into position 17, in which relay 334 is energized in a cii'cuit'over sequence switch contact 342 top, back contact of relay 326 and sequence switch contact 340 bottom. vRelay 323 is again energized over front contact of relay 334. sequence switch 320 is energized over front contact of relay 323 and starts from position 17 and moves into position 1..

After the fundamental circuit hasbeeu opened at the register set, the relay 452 is dccnern'izcd a. soon as contact 457 top is opened. the power magnet is disconnected and sequence switch 450 is energized in a circuit over back contact of relay 452.

The holding magnet 465i is connected in parallel to the sequence switch. The brush C211 riage is arrested and sequence switch 450 starts from position When the sequence switch'of the final selecloi: reaches position 8, the wanted line undergoes a test and the right-hand highresistanco. winding of test relay. 464 is connected in a circuit overthe cutoff relaybf "the want-ed line. If the'l-ine is 'freey're'lay lltl 46 brings into circuit over its tront contact its left-hand low-resistance winding, toether with winding of relay 462 in parallel to its high-resistance winding. The terminal of the wanted line is so made busy, Whereas relay 462 is energized. Sequence switch 50, in reaching position 10, is energized in the circuit over "r'ront contact oi relay 462, and moves over positions 10' and i1 into position 12, in which an alternating ringing current is immediately sent to the station of the wanted line. Relay 4152 is brought into connection with a common interrupter 469, which when closed, causes the energization of said relay, which at its front contact completes a circuit to move sequence switch i 30 into position .13, in which relay are is connected with a further common interrupter 472. The two interrupters res and 4:72 are continuously operated and are arranged to close the circuit to ground. at predetermined intervals, so that after the sequence switch 450 reaches position 12, it is brought after the lapse of a few seconds, over position 12 and 13 into position l t.

When sequence switch e30 reaches position 1e, toe direct connection of the ringing current is removed, and the connection of the subscribers line alternately with the source of ringing current, and gound is maintained over for the usual intervals by means of int rrupter r74. During the time sequence switch 450 is in positions 12 to 14 the primary winding of tone coil l7? is connected to a common interrupter, and the secondary windings of coil 4-77 connected in bridge to the line. The calling subscriber perceives an indication that the ringing of the called party is proceeding. soon as at the wanted station the receiver is lifted from the hook, the ringing relay 100 is energized and causes over its front contact the energization of sequence switch s50, which starts from position 1 1 and moves into position 15, in which a through connection of the called subscribers line is made to the transmitter current supply bridge at the first group selector. Relay 262 is energized. Sequence switch 220 starts from position 11 and moves into position 12.

It the number ot the wanted subscriber begins with the figure 2 and the wanted number is, for example, the ten thousands register 100 is finally set. in posi tion 9. When the fundamental circuit is l LS closed over relay of the first ,(i1'0UP selector, the thousands register U0 is first restored to position 0 and then the ten thousands register 100. The trip spindle of the first group selector makes an additional step. The brush carriage of the first group selector searches now in an even level for a tree trunk line to a distant exchange. On the incoming end of the trunk line is provided asecond group selector, as shown in Figure 7. The fundamental circuit, when extended to the first group selector over the sequence switch contacts 2&7 and 255, is closed on the distant end of the two-wire trunk line at the contacts 504 and 505 through relay 522 of the second group selector to ground. Sequence switch 520 is thereby energized over contact 506, and front contact of relay 522 starts from position 1 and moves into position 2, in which the trip spindle 508 is energized in a circuit over sequence switch contact 507 top and front contact of relay 522. The trip spindle rotates and at its contact 510 top over sequence switch contact 509 bottom provides short-circuitings tor the fundamental circuit. After the fundamental circuit is opened, both at the register set and at contact 510 of the trip spindle, relay is deenergized and sequence switch 520 is energized in a circuit over contact 511 top and back contact of relay 522. Sequence switch 520 starts from position 2 and moves into position 5, in which the power magnet of the brush carriage 531 energized in a circuit over sequence switch contact 51% bottom and back contact of test relay 532. The left-hand high-resistance winding of the other test relay 53 i is thereby connected over sequence switch contact 513 bottom to test brush The brush carriage rotates, moving the brushes along the terminal row determined by the position of the trip spindle, and searches for a final selector such as shown in Figure 6. When the final selector has been found, relay 5% is energized, and the test terminal of the final selector is made busy. Also, relay 532 is energized and sequence switch 520 is energized in a circuit over contact 506 bottom and 'ront contact of relay 532. During the time sequence switch 520 remains in position 5, both windings of the release control relay 523, together with the retardation coil 52s, are brought in bridge ot the trunk line over sequence switch contacts 50 i top and 505 top,

Sequence switch 350 at the register set in the exchange, after the control of the fundamental circuit tor the second group selector is completed, moves as has been described into position'9. A circuit is established over sequence switch contacts 358 top and top through relay 377, which together with relay 523 in the Ilistant exchange, is energized in a metallic circuit over the trunk line before sequence switch 850 reaches position Ftlielay 353 is energized in a circuit over front contact oi relay 3?? and contact 370 of sequence switch 350. Belay 353 maintains its energization over its lett-hand front contactindependent oi sequence switch contacts 370, and opens on its right-hand back contactthe connection with sequence switch contact uence switch 350 is discon- 9,, When the sequence switch 520 on the second group selector in the distant exchange is energized over ffront contact ofrelay532 and leaves postion 5, the circuit over'the trunk line is opened :at the sequence switch contacts505 and 504 during the time sequence switch 520 moves over position In positions 7 and 8 of'sequence switch 520, the circuit including relay is again closed. The opening-of the trunk line causes the deenergization ofrelay 377 an-d'in consequence of :relay353, but as soon asthe trunk lineiis again closed, relay 523 is again energized. Sequence switch 520 isarrested in position 8 and remains there waiting until. sequence switch 350 of the register set becomes energized in the circuit over contact- 31 of'sequente switch 320, which can take place when the dialing has been completed and sequence switch 320 is advanced into position '14. hen sequence switch v350 leaves position '9, the circuit containing the battery and relay 377 is broken at contact 358 top and 356 top. Belay 523 "is deenergized, and sequence switch 520 is energized in acircuit over its contact506=top and back cont-act of :relay 523.

Sequence switch 520 starts from position 8 and moves into position 10. When passing position 9, a circuit is closed io'rthe energization of'relay 452 of the final: selec'tor'over-con tact 444 of sequenceswi-tch 450, contact 515 bottom and contact 517 of sequence switch 520, sothat relay 452 causes theenergization ofsequence switch 450and its starting from position 1. Sequence switch contact 516 is closed before sequence-switch contact 517 ,is opened, and the circuit is extended to :the relay 355:ofthea'egister set'in the exchange, after which the final selector is set up under the control of the tens'and units registenas has been described, and it has been secured that thesecond group selector on a'two-wire trunk cannot produce the starting impulse for the sequence switch of the final selector unless the register set is ready to control the final selector, while the register set prevents the preparation ofthe fundamental circuit until a free trunk line to a final selector has beenselectcd. When the sequence switch 450 of the final selector leaves position 5, resistance 442 vis disconnected ,at contact 14-1 and th high-resistance winding of relay 443 is left alone inthe circuit of relay 532, which is thereby deenergized. Sequence switch 520 is therebv ener' ized in a circuit 'o'ver contact 514 top and back contact of relay 532. Se

quence switch 520 starts from position 10 and moves into position 15, m which relay 523 is again brought in bridge to the trunk line, while supervisory relay 525, together with retardation coil 526 is brought over sequenceswitch contacts 515 and 516 in connection wit'lrthe final selector.

The-"closure of contacts 368 bottom of sequence switch 350 on :the register set is so timed that sequence switch 220 of the cord is advanced into position 10, after :the sequence switch of the final selector :has *ileft position 5 land has opened its contacts 444 and 445, while sequence switch 220 reaches position :10 before sequence switch 520 of a group selector on the end of a two-wire trunk reaches its position '15, so that :rela'y 523 is energized in a metallic circuitover re lay 262-and retardation coil 257. When :the called subscriber answers and the sequence switch of 'the final selector moves into position 15, theitransmitter.current supplytozthe calling station is provided over relay 52-5 and retardation coil 526, and relay 525 is tenergized and provides a shunt around the high resistance winding of relay 523. {Re lay 262 is thereby energized and sequence switch 220 advan-ces'into position 12. i

If the second'figure of the wanted number is odd, the first group selector is set up to a level as if the lower even figure has been dialed, whereas the second ,group selector is advanced to another level producing thereby the second translation on :the switches. Assuming that the number of the wanted subscriber was 113,453, register 110 receives seven impulses and is arrested :in position 7 When Sequence switch 350 moves over position 2, zrela'y 360 iisienergized in a circuit over contact 116 or" register 110, contact 137 1 bottom and-contact 351 of-sequence switch 350. Belay360 maintains its energization over itsright-hand front contact and sequence switch rCOlllLiLCi) Y 372 top. Over the -left-;ha:nd contact of .relay 360 l-theqcircuit utor register .110 is so modified that this register, gwihen underthecontrol of the'stepping i'ela 355, is arrested in position 9 instead of position 0. The circuittherefore.

when next closed,-extends over back contacts of ,rela-y'355 and relay 359, contac-t361 of sequence switch 350 and contact 113 (of register 110, left-hand front contact of re lay 360, contact 1151of-register 1'10 and contact 104 of register 100' to the sequence switch 350 and relay 357. The trip spindle of the "first group selector :takes thereforeposition 10, while the :next subsequent de ener iza'tionbf rela :3-55causes the o )ening of;the fundamental circuit; Each time-the i been dialed.

half of a terminal second digit dialed is odd, the trip spindle oi the second group selector makes therefore an additional step.

It the third digit of the wanted number is odd, as for example the number 12353, register 120 receives from the dial five i1n pulses, and is arrested in position 5. hen sequence switch 350 moves over position relays 373 and 374 are energized in a circuit over contact 375 top of sequence switch and contact 126 of register 120, whereby relay 373 provides a locking circuit over its front contact, and sequence switch contact 372 bottom. After the units register 140 has been set up, the energization of relays 373 and an is maintained over contact 1 16 of register 14:0 and contact 369 of sequence switch 350. W hen sequence switch 350 passes over position 5, register 120 is energized in a circuit over its contact 122, contact 366 top of sequence switch 350 and contact 126 01? register 120. Register 120 makes an additional step and takes the same position it the next lower even digit had The trip spindle of a second selector takes therefore the same position, disregarding whether the third figure of the wanted number was even or odd, and relay 374: controls the translation for the units of the final selector, causing the advance of the brush carriage oi: the second half of the terminal row.

W hen the brush carriage of a final selector moves between the first and second half of the terminal arc, the short-circuiting contact 4:57 of the brush carriage is in the wellknown manner closed for a comparatively longer time, and if the wanted number corresponds to the first terminal in the second arc, the long closure or contacts 4-57 is delaying the starting of sequence switch 450 and opening or" contact t l L. In order that tne sequence switch 220 01' the cord shall not move into position 10 before contact an is opened at a final selector, the circuit at the register is so arranged that it the wanted number is the first in the second half of the terminal arc of a final selector, the energization of relay 339, and in consequence, the deenergization of relay 222. is correspondingly delayed. The first terminal on the second half of the terminal arc corresponds to an odd position of i. ister l20 and position of register It, theretorarelay 373 has been energized on an odd position of register 120, and if register 1& has received ten impulses from the dial and is arrested in its position 0, a circuit is closed in position 10 of sequence switch 350 for the energization of relay 365 over contact 1a.) of register 1 10, contact 37 bottom of sequence switch 350, front contact of relay 373 and sequence switch contact 3? 2 bottom. Relay 365 once energized, maintains-its energization over switch contact its left-hand front contact and sequence switch contact 369 bottom. ll hen, alter the completion of the selection, sequence switch 350 reaches position 13, the circuit for relay 339 is maintained opened at the leftha'nd back contact of relay 365, and this circuit is closed in position 1 1 of sequence switch 350 over the sequence switch contact 368 top, front contact of relay 365 and sequence switch contact 369.

l Vhen, after a conversation, the calling subscriber restores his receiver on the hook relay 231 is deenergized and sequence switch 220 starts from position 12 and moves over position 13 into position '17. When the se quence switch 220 moves over positions 14: to 16, the metering battery 259 is connected to terminal 238, whereby the meter 208 at the calling subscribersline is operated. In position 17 of sequence switch 220 the magnet 21-1 is energized, and the brush carriage rotates until its home contact 269 is reached, when relay 232 is energized in a circuit over contact 269. The brush carriage is arrested and sequence switch 220 starts from position 17 and moves into position 18.

After sequence switch 220 leaves position 12, the brushes of the first group selector are disconnected. H the connection has been established over a local second group selector, as shown in Figure 5, relay 4.03 is deenergized and sequence switch 420 is energized. in a circuit over sequence an and back contact of re lay e03. Sequence switch 420 starts from position and moves over position into position 1?, in which power magnet 4:31 is again energized in the circuit over sequence switch contact 4:14: and back contact of relay 4e32, and the brush carriage of the group selector is restored to its position of rest, and when. the hon'ie contact 493 is closed, relay 432 is energized in a circuit over contact 439 and sequence switch contact 101. The power magnet431 is disconnected on the hack contact of relay res and sequence switch 420 is energized in the circuit over the front contact of this relay. In parallel to sequence switch 120 is connected over its contact 411 the hold ing magnet 435, the brush carriage is arrest-ed, whereas sequence switch 420 s arts from its position 17 and moves into its position 1..

After sequence switch 420 leaves position 15 audits contact 4-13 top is opened, 44-3 at the final selector is deei'iergized and sequence switch 450 starts from position 15 and moves into position 17. Relay is brought over sequence switch contact sec bottom in connection with the called line, and it the called subscriber has not restored his receiver to the hook, relay 452 is energized, sequence switch s is held in position relay Cir Vented through the disconnection of tl e metering battery 259 at the left-hand back contact of relay 224.

When the release is started, before the dialing is completed, relay 339 is energized in one of the positions 7%, 9-1; or 11- oi sequence switch 320, and when the connection is given up at the calling subscribers station, after the wanted number has been dialed but-before the selection is completed, sequence switch 320 is energized in. position is over contact 348 bottom and back contact of relay in position l5 relay 339 is energized in the circuit over sequence switch contact 84-8 top and lJttCr-i contact ct relay so that relay 222 in the cord is deen gised. During the premature release of the register set, sequence switch 350 is moved without delay over tie positions in which the fundamental circuit of the selectors can be closed. "When sequence switch reaches position 15, sequence switch is energized in a circuit over contact 371 top and contact 346 bottom of equence switch 320. Sequence switch 350 moves from the position in which the premature release started over position 12 into position 15, in which a check is made to determine whether or not the registers 120, and 100 are in their position of rest. At contact of sequence s itch 820 the back contact of relay 359 is connected to ground, and the circuit is established for the resetting of the regis ters, should they not be in position 0, over contact 343 of sequence switch 2320, contact 366 oi sequence switch 350 and contact 122 of register 120, After register reaches position 0, a circuit is extended over contact 124 of register 120 and contact 361 of sequence switch 350 to register 110, and after this register is in its position 0, the circuit extended over contact 364. of sequence switch 350, contact 11 of register 110 to ref 1' 100. After this register is in position 0, the circuit is extended over contact 10 iand quence switch contact 363 to sequence switch 350. Sequence switch. 350 then starts from position 15 and moves into position 16, in which a check is made to determine whether 1' not the tens register is in position 0, and a circuit is established over contact B l of sequence switch 320, contact 367 of sequence switch 350 and contacts 132 of register 130. After this register is in position 0, the circuit is extended to sequence switch 350 which is then energized over contact and contact 134 of register 130. Sequence switch 350 starts from position 16 and moves into position 17, in which a check is made to determine whether or not the units register is in position 0. A circuit is established over contact 343 of sequence switch 320, and contact 367 bottom of sequence switch 350 to register 140. When register 140 is in position 0, the circuit is extended over contact 1&3, back contact of relay 37 i, contact l ll of register 140 to sequence switch contact Sequence switch 350 starts from position 1'? and moves into position i, in which relay 323 is ener ized, as has been described.

When a release is started and relay 222 is dcenergized, at a stage in which sequence switch 220 of the cord is in position. 7, relay 22 iis energized as soon as sequence switch 220 reaches position 8. The sequence switch remains in position 8 until the brush carria' is restored to its position of rest. Relay 222 remains connected over sequence. switch con tact 2&6 top to conductor 293. It is therefore desirous that the register set shall. not be:

given free and shall not be taken for a new call. until contact 24 6 of the cord which has been released is opened It the sequence switch 320 reaches position 17 before contact 2% of sequence switch 220 is opened, a circuit is established for the energization of relay 826 over back contact of relay 323, contact 327 top of sequence switch 320, wire 293, contact 246 top of sequence switch 220 and winding of 222. {Sequence switch 320 is held in position 17 until relay 326 is I energized.

When a release is started during the progress of a selection on which a local second group selector as shown in Figure 5 is used, relay 403 is deenergized as soon as relay 22% is energized, and its right-hand baclr contact is opened. lVhen the release is started at the time the fundamental circuit is closed on the register set, for the setting up of the trip spindle of the second select-or, sequence switch 350 is in position 6, and the left-hand winding of relay 357 is energized in circuit over contact 376 bottom of sequence switch 350 and right-hand front contact of relay The fundamental circuitis opened at the back contact of relay 357, relay 422 at the second group selector is deenergized, and sequence switch 120 starts from position Before sequence switch 420 reaches position is, relay 222 in the cord is already energized, and relay 403 is decnergized. In position of sequence switch 120, its energization is maintained over baci: contact of relay 403, whereby the holding magnet 435 is also energized, and the brush carriage is held in position of rest. lin position 6 of sequence switch 4-20, relay 432 is energized in the circuit over the home contact 439, and the energization of sequence switch 420 is maintained in position 6, over front contact of relay 432. Sequence switch 420 then completes its rotation and is arr-ester in position 1. t the release is started, and relay 403 becomes deenergized at the time se quence switch 420 is in position 5, in which the circuit for searching of a free terminal to a following selector is closed, sernience switch 4,20 is energized over back contact loo lll)

of relay 403, and moves immediately over position 5, into position 6, in which the power ma net ibl is maintained energized and the brush carriage is restored to its position oi rest without the test relay 434 testing the terminals. W hen the contact 439 is closed, relay L32 is energized and sequence switch 420 moves out from position 6 and completes its rotation.

It the release is extended to the second group selector, after connection with the terminals oi. a tree final has been obtained and sequence switch @250 has left position 1, thri'iugh the closure ot the fundamental circult in the register set, relay 452 remaining deenergizcd for a longer interval, enables sequence switch to pass over positions 2 and 5, and to disconnect resistance before the sequence switch 420 of the secmnd group selector leaves position 15, and terminal is given tree, so that the high resistance relay i l3 hinders the connection of another second group selector until sequence switch 450 has completed its operation. and reaches position 1.

ll hcn release is started and the fundamental circuit is opened, at the time the rush carriage of a final selector is rotating under the control of the register set. along the terminals of the subscribers lines, it is essential that during the release a subscribefis lino shall not be disturbed through sequence switch 450 completing its rotation. Sequence switch always advanced over position 15 before sequence switch 450 reaches position 11, so that relay is deenergized through opening of the front contact of relay 443, and the brush carriage of the final selector is restarted in position 11 of the sequence switch in the same manner as has been described in the case of the calling line being found busy. In this way the release of the sequence switch of a l selector is accomplished without disturbing the subscribers line on which the brushes may happen to stay, whenever the release is started before the selection under the .ntrol oil the register set is completed.

Of special importance are releases during the progress of a selection over a two--wire trunk line to a distant exchange. The fundamental circuit at the register set may be opened during the time sequence switch 520 is in position 2, and sequence switch 350 on the register set is in position 6. The fundamental circuit is opened immediately relay 357 is energized in a circuit over sequence switch contact 376 bottom and front contact of relay 339. This determines the moment of opening of the fundamental circuit, independent of the position of sequence switch 320. Sequence switch 520 on the incoming en ot' the trunk line. when started from po- 5 .n 2. will reach position 5 betore sequence switch leaves position 6, unless the resto- %20 at such a premature release is ration or" registers 120 and 110 has been already completed, because the circuit for register 120 and 110 and sequence switch contact 350 is held opened at the back contact of relay 359 until sequence switch 320 reaches position 15'and closes contact bottom. Relay 523 is deenergized when sequence switch 520 reaches position 5, and relay 522 is energized in the circuit over sequence switch contact 509 top and back contact of relay 523. Sequence switch 520 is energized over front contact of relay 522, leaves position 5 and moves into position 6, in which relay 532 is energized over contact 539, maintaining the energization of sequence switch 520 which completes its rotation. It the subscriber has completed the dialing, but the selection has been delayed at the first group selector, and the release is started at the moment sequence switch 320 is in position 15, while sequence switch 350 is in position 6, sequence switch 520 does not reach position 5 before contacts top and 356 top of sequence switch 350 are closed. Relay 523 on the second group selector is thereby energized and the brush carriage can start to rotate. The sequence switch 350 leaves position 9 and relay 523 becomes de-' energized before the brushes are able to reach the first terminal. Sequence switch 520 will then be energized, as has been described, and moved into position 6, in which the brush carriage is restored to its position of rest.

When the release starts at some later time, during which the brush carriages of the second group selector are rotating, the deenergization of relay 523, through sequence switch 350 leaving position 9. may happen at the instant a free terminal of a final selector is reached. Relay 53% becomes energized and the terminal is made busy. Sequence switch 520 is arrested in position 10. The energization of relay 452 of the final selector over the passing contact 5i? of the sequence switch 520 prevents a hanging up of this sequence switch. in that sequence switch e250 of the final selectorstarts from position 1, and in passing positions 2 and 5, disconnects resistance 442and causes relay 532 to deenergize. Sequence switch 520 starts from position 10 and the second group selector is re leased. The energization of relay 224 of the cord is at such a release slightly delayed in that relay 222 is maintained energized over contact 330 of sequence switch 350. left-hand back contact of 378 and sequence switch contact 369 until sequence switch 350 passes position 12. This makes it certain that the outgoing end of a two wire trunk is maintained lousy until the sequence switch of the final selector has passed. position 5, so that relay 452 could not be energized over the two-wire trunk line and the fundamental circuit of a new call.

When the dial at the subscribers station is set up to a higher number than the capacity of the exchange, and the first figure dialed is different from Figure 1 or 2, t ie register in the exchange takes a position different from position 9 or 0. If the subscriber does not notice his mistake, he obtains a connection in the exchange over a special line with the supervisory operator, who cal Ls the attention of the subscriber to the error made. If register 100 takes a position different from position 9 or 0, sequence. switch 350 cannot start from position 1 after sequence switch 320 reaches position 6, since the circuit for the energization of sequence switch 350 is maintained opened at contact 103 oi' regi r 100. The other registers are moreover prevented from receiving impulses from the stepping relay through opening of contact 105 on register 100, and these registers remain in position 0, and after each series of impulses from the dial, relay is energized and the sequence switch is advanced. to its next position. After the subscriber completes the dialing and sequence switch 320 moves into position 1 1, sequence switch 350 is energized in a circuit over contact 352, back contact of relay 353 and contact 3 11 bottom of sequence switch 320. Sequence switch 3530 starts from position 1 and moves into position 3. he fundamental circuit is then closed to the first group selector and its trip spindle, when rotating, controls the resetting of register 100 and the selecting of a level corresponding to the first figure dialed. Since the following registers are in their 0 position, a number is selected consisting of four figures, of which the first is the same as the first figure dialed, and the remaining figures are 0.

For obtaining a connection with a recording or atoll operator in the manual toll board, the subscriber in the automatic 8X- change dials a predetermined number con-- sisting of three figures. The subscriber dials the inunber 292, register 100 takes the position 9, register takes the position 1, and t er 12(7) position 8. When sequence switch 320 reaches position 6 and sequence switch 350 is started from position 1, as has been described, relay 378 is energized in a circuit over sequence switch contacts 351 and 371 bottom and contact 117 of register 110. Relay 378 provides a holding circuit for its winding over its left-hand front contact and sequence switch contact 369 top. When the fundamental circuit is first closed in position 3 of sequence switch 350, the trip spindle of the first group selector is advanced to a position according to the positions of registers 110 and 100. The first group selector finds a free trunk line, and the trip spindle of the second group selector provides the restoration of registers 120 and 110 to their 0 position. The second group selector then searches for a free trunk such as shown in Figure 8. Sequence switch 359 is thereby advanced into position 10, regardless of the position of sequence switch 320, and the circuit for the energization of sequence switch 359 is closed from battery through the winding of sequence switch magnet 350, Contact 352, top, contact and 1 l armature of relay 353, front i ght-nanc contact and right-hand armature of relay 378, contact 379, bottom, to ground.

As soon as the brushes of the second group selector reach a free trunk line, test relay 134 is energized over terminal 612, left-hand back contact of relay 613, and winding of relay 61 1. Sequence switch 120 of the second group selector is started from position 5 and moves into position 10, while relay 61 1 is energized, and provides on its front contact a circuit for lamp 618 including right-hand back contacts of relays 613 and 620. Lamp 618 lights. In position 16 of sequence switch 120 a metallic circuit is established including relays 615 and 616 of Figure 3, and relays 377 and 355 at the register set, the shunt around the winding of relay 37 7 being removed at the back contact of relay 378. The high resistance winding of relay 377 prevents the operation of relays 615 and 616, and relay 377 provides a circuit for the energization of relay 339 over front contact of relay 377 and contacts 370 top of sequence switch 350. On the deenergization of relay 222 of the cord through opening of its circuit at the back contact of relay 339, sequence switch 220 of the cord is advanced from position 9 into position 10, whereby relay 325 in the register set is deenergized, and sequence switch 320 continues its rotation, and when reaching position 15 causes the energization of sequence switch 350 over contact 3 12 of sequence switch 320. Sequence switch 350 is moved over positions 12 and 15 into position 16. The tens register is in position 1, having been energized in completing one step when the circuit on the subscriber line was closed after the third series of impulses on the dial. Register is thereby restored to its 0 position, as has been described, sequence switch 350 starts from position 16 and moves over position 17 into position 1, after which sequence switch 320 is also moved into position 1.

l Vhen the sequence switch of the cord reaches position 10, relay 262 is energized in a circuit over contact 256 of sequence switch 220, contact 115 of sequence switch 420, lefthand back contact of relay 617 winding of relay 615, and back contact of relay 613. A

further circuit is established for the ener gization of relay 616, over right-hand back contact of relay 617, contact 416 of sequence switch 420, contact 255 ofsequence switch 220, retardation coil 257 and front contact loo lit) 

